Inspired by dixeyk and Ned, I wanted to do a quick comparison for you folks with my collection of 50mm legacy lenses. This is as non scientific as you can get but I just wanted to share what you would get with each lens.

I will be taking 2 shots with each. One at f/2.8 and one at f/8. WB is set to shade and all shots are taken with a OLY E-PL1 @ ISO 200. Here is a picture of the setup.

Your Asahi Super-Takumar appears to be radioactive. That is what is turning the glass yellow. You can bleach the glass by putting in sunlight, but since it is low-level radioactive material, you may want to get rid of it...

Your Asahi Super-Takumar appears to be radioactive. That is what is turning the glass yellow. You can bleach the glass by putting in sunlight, but since it is low-level radioactive material, you may want to get rid of it...

Its got a weird 60's vibe to it that various camera-phone apps seem to aspire to include as a filter these days.

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HA!..I hear you...I guess I never noticed that much in the past due to the fact I shoot B&W about 90% of the time but I am taking care of that right now. I have it in my home made UV light box. A couple days in there should do her some good

I like the Canon FD and the Minolta quite a lot...especially the Rokkor at 2.8 but the one that stands out to me is the Super Tak (yellowing and all). After seeing your setupI tea;ice I need to redo mine with a tripod and get more serious :big grin:.

Tomorrow is supposed to be sunny...maybe I can get out and do a round III (bokeh).

I like the Canon FD and the Minolta quite a lot...especially the Rokkor at 2.8 but the one that stands out to me is the Super Tak (yellowing and all). After seeing your setupI tea;ice I need to redo mine with a tripod and get more serious :big grin:.

Tomorrow is supposed to be sunny...maybe I can get out and do a round III (bokeh).

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That sounds good....I think the next test will be a B&W show down.. Round IV :smile:

The radioactivity and glass really peaked my interest ... so I goggled and this was the first link I read ...

"I was recently reading some previous postings and web articles about certain lens glasses containing radioactive elements, and wondered if any of my collection might be 'hot'.<br>Initially, I was more curious than worried, but after doing some tests, I'm now definitely worried, and I think my findings deserve wider attention.<p>I have a sample of a 7" Kodak Aero-Ektar, which is a lens that has a big reputation for being potentially radioactive.<br>However, all the articles I've read state that the radioactivity is mainly in the form of alpha emmission, and shouldn't give much call for concern, since alpha particles are quite low energy, and easily stopped by any solid object. I'm told that alpha particles can only penetrate about 40 microns into human tissue.<br>Anyway, to cut to the chase: I just got our radiation protection officer to run a geiger counter and a dosimeter over the Aero-Ektar, and he found that the rear element was quite hot, giving about 200 counts/second. Worse yet, we discovered that it was mainly GAMMA emmission, since even an inch of perspex and a steel plate hardly affected the counts at all. The active element used in making the glass is Thorium, and a quick check of the table of its decay products confirmed that they're mostly gamma emmitters, after about 6 years of decay.<br>Dosimeter readings showed that within 1" of the rear lens surface, the dose was above the limit allowed for monitored radiation workers, and only fell to the publicly allowable safe limit at more than 6" from the lens.<br>I don't think I'll be using that lens as a paperweight, or handling it too much from now on. By all modern standards, that lens would be classed as downright hazardous, and not to be used without protective clothing!<br>I'll be testing the rest of my lenses as potential gamma sources as well in the near future."

To be honest, I am not sure the difference between the Tak and Aero-Ektar. The Kodak lens is older and much more massive--they tested one at RIT by putting it on a piece of film for a week or so and developed it, a circular image was formed. Still, with everything in the environment, I am not sure I would want to hang onto a known radioactive source.

BTW, hot (radioactive) glass was used in early 20th microscope eyepieces until they found they were damaging operator eyes.

The radioactivity and glass really peaked my interest ... so I goggled and this was the first link I read ...

"I was recently reading some previous postings and web articles about certain lens glasses containing radioactive elements, and wondered if any of my collection might be 'hot'.<br>Initially, I was more curious than worried, but after doing some tests, I'm now definitely worried, and I think my findings deserve wider attention.<p>I have a sample of a 7" Kodak Aero-Ektar, which is a lens that has a big reputation for being potentially radioactive.<br>However, all the articles I've read state that the radioactivity is mainly in the form of alpha emmission, and shouldn't give much call for concern, since alpha particles are quite low energy, and easily stopped by any solid object. I'm told that alpha particles can only penetrate about 40 microns into human tissue.<br>Anyway, to cut to the chase: I just got our radiation protection officer to run a geiger counter and a dosimeter over the Aero-Ektar, and he found that the rear element was quite hot, giving about 200 counts/second. Worse yet, we discovered that it was mainly GAMMA emmission, since even an inch of perspex and a steel plate hardly affected the counts at all. The active element used in making the glass is Thorium, and a quick check of the table of its decay products confirmed that they're mostly gamma emmitters, after about 6 years of decay.<br>Dosimeter readings showed that within 1" of the rear lens surface, the dose was above the limit allowed for monitored radiation workers, and only fell to the publicly allowable safe limit at more than 6" from the lens.<br>I don't think I'll be using that lens as a paperweight, or handling it too much from now on. By all modern standards, that lens would be classed as downright hazardous, and not to be used without protective clothing!<br>I'll be testing the rest of my lenses as potential gamma sources as well in the near future."

I think Hikari is right again ... dump the lens.

G

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I hear you guys.. and I have seen those vids on youtube, even though this was not the point of my thread post I think I will keep it. It takes wonderful pictures that I just cant get out of todays glass. On that note, I will make sure not to put the lens to close to my nads

LOL...that was so wrong in so many ways. I have had the lens in a home made UV box the better part of the day and I can already see it clearing up. Ill give it a couple more days and post what it looks like and see if it clears up.

It was news to me as well, hence the Google. The SMC Takumar 50/1.4 has Thorium doped lenses. Thorium, named after the Norse God Thor, is a natural radioactive chemical element. Thorium was used to obtain larger refraction ratio and keep relatively low dispersion at the same time.

I was under the impression that the Super Takumar 50/1.4 and the S-M-C Takumar 50/1.4 (with scalloped metal focus ring) had the radioactive element, but the slightly later SMC Takumar 50/1.4 (with the rubber focus ring) did not. But some quick searching turns up inconsistent reports...all I know is that my SMC Takumar is not yellowing, but maybe I should find someone with a geiger counter and check it out!

It was news to me as well, hence the Google. The SMC Takumar 50/1.4 has Thorium doped lenses. Thorium, named after the Norse God Thor, is a natural radioactive chemical element. Thorium was used to obtain larger refraction ratio and keep relatively low dispersion at the same time.

Gary

PS- Also, you can read the aperture numbers in the dark.
G

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Well I plan to tell my family members who have old lenses, especially SMC takumar . Even when the lens is disposed or hammered, I believe the glass still has radioactive element? I still don't have any idea what to do. It can harm other people if it isn't disposed well

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About the sharpness, it seems yashica and minolta are sharper than the others? Although I like the color from the radioactive one..it has gorgeous yellow

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